bulb durability

[Ratyoke]

Hi, I've been lurking for a while, but this is my first post.

I have a question: I was wondering if flashing and incandescent light on and off real fast is hard on the bulb? I have a few Surefires, and it seems that when ever my friends are around them they will pick one up and play with it. Usually flashing it on and off, which bugs the hell out of me, regardless of bulb wear. I have also had 2 bulbs go out prematurely, and that makes me kind of paranoid about my bulbs going out.


Thanks
Jon

 

[R11GS]

I don't know the "official" answer.


I do know I've had a SF 6P for nearly a decade running the same P61 (high output) bulb and that it is typically only "flashed" on; rarely left on for more than ten or twenty seconds at a flash. While it hasn't been used a "lot"; I've likely run no more than a dozen sets of batteries over the decade I've had it, if it can do that, I'm not really concerned.

 

[Ratyoke]

Wow, replies come so fast here.

I usually only use my lights for less than 30 seconds at a time, but what I am talking about my friends doing is flashing them on and off as fast as they can.

 

[LEDAdd1ct]

Generally speaking, anything that experiences heat expands, and anything that experiences a relative cooling contracts. So, my guess would be that with an incandescent, which depends on an intact filament to function, the more times a light is cycled, the shorter its span will be. But I would prefer others to back me up on this.

LEDAdd1ct

 

[Size15's]

Welcome to CPF Jon!

Did you give SureFire a call about those premature failures?

I have quite a few SureFires and mostly use them momentary-on/off rather than constant-on. There is no discernible difference in bulb lifespan or durability as a result of not 'flashing' it.

Al

 

[mdocod]

same thing happens to me whenever I hand a light to someone, and like you, it bugs me that they are cycling the heck out of my expensive xenon globe, Though I haven't had many failures, It still bugs me...

solution to the problem is as follows: hand them LED lights, they can flash em all day and all night and you can rest easy.

 

[R11GS]

My friends will "flash" mine too, and for some reason that has never bothered me a lick. Heck, they're called FLASHlights! LOL OTOH, I always get anxious when instead of simply flashing my lights, they turn them on continuously. I can just feel the battery meter running! High intensity incandescent are the worst of course, but even a high bright LED gives me the creepies when they just leave 'em run on bright for no good reason...

 

[Retinator]

I also believe that flashing will shorten the lifespan of the bulb, but to what extent?

I'd expect dropping the light would shorten the span more than flashing it.
Even traveling with the light, the vibration would affect it, but probably only marginally.

I'd worry more about killing the batts more than the bulb. As long as they're not rough with the light, I'd be ok myself. You might want to either keep them away from the 'kids' lol or get them an LED to play with.

And hey, if they're THAT interested in them, you might be able to bring them over to our side :devil: Xmas is coming too

 

[jumpstat]

I do agree that flashing a incan would degenerate its lifespan. Take a look at the bulbs in your house. It last longer if the bulbs are switch on to its working parameters rather than flashing like a strobe. Can't really confirm it though. Shock loading is more severe on the filaments and for high drain bulbs, the batteries are the ones to look out for....my 2 cents

 

[Ratyoke]

Thanks for the replies. I will tell my friends it is bad for the bulb whether it really is or not. One of these friends of mine is a cop and has a SF M2, and a couple Streamlight rechargables. He should play with his own lights.

I have had experience with what a drop can do to a bulb. I dropped my old SF 6Z about 3-4 feet in the street and the bulb went out. And I was on vacation and didn't have a spare with me. About 2 years ago (after the 6z was stolen) I got an M3, and the high power bulb went out during the 2nd set of batteries I had used in the light. That really made me think I should start using led lights instead. I should have called Surefire about the M3, but I didn't. I don't know why.

 

[Size15's]

My personal opinion is that the light should be used in the way it needs to be used - if that means flashing it then that is a legitimate use.
If as a result the bulb lifespan is shortened then so be it.

There is no way to determine whether flashing a bulb reduces its lifespan. Certainly not in any measurable way.

Worrying about flashing a flashlight is a non issue in my opinion.

Al

 

[Daniel_sk]

It shortens the bulb's lifespan - but I don't know "how much". That's why I like a soft-start feature in the Surefire A2.

 

[ampdude]

Hi, I've been lurking for a while, but this is my first post.

I have a question: I was wondering if flashing and incandescent light on and off real fast is hard on the bulb? I have a few Surefires, and it seems that when ever my friends are around them they will pick one up and play with it. Usually flashing it on and off, which bugs the hell out of me, regardless of bulb wear. I have also had 2 bulbs go out prematurely, and that makes me kind of paranoid about my bulbs going out.


Thanks
Jon

God that bugs me too! Makes me want to swear just thinking about it because people always do that. I don't know why when you hand a light to some people they feel like they have to start flashing it on and off over and over again. I've just stopped showing people lights basically.

Though to be honest I have some xenon lamps with ALOT of use on them. And ALOT of turning off and on. And some of them were heavily used when I got them. I've never burned any out though.

 

[ADDICTED2LITE]

I don't know if household bulbs are designed different than flashlight bulbs, but an AC incandescent house bulb flashes 60 times per second.

 

[pfccypret]

All I do is flash my lights. Newer police techniques taught for building searches involve "strobing the lights" whether or not you have an LED that has a strobe setting or an incan that you have to manually strobe. It's almost a habit, hand me a light with a tail switch and I will start flashing.

For actual use, 95% of the time I need my flashlight, I will flash it. A few seconds of light is all that is needed. Maybe to look at something, maybe to just see the path ahead of me, ect.

Personally, I have not noticed too much of a difference between constant use and flashing.

 

[Flipside]

Some dimmers use PWM, effectively flashing the light on and off at a very high frequency. (Some of those who can still hear well will notice a whine or hum with this kind of dimmer) So, unless you're direct drive, DC power, the dimmer is already flashing your light for you.

 

[mudman cj]

I don't know if household bulbs are designed different than flashlight bulbs, but an AC incandescent house bulb flashes 60 times per second.

True, but this is different than when the light is turned on cold. When the filament is cold is has low resistance, so a surge of current passes through it. This causes vaporization of tungsten primarily at the thinnest spot in the filament (because it has the highest resistance and heat=current^2*R).